Retail Antitheft Scanners Interfere with Heart Pacemakers
April 11, 2000 (Atlanta) -- Electronic antitheft system scanners, frequently
used by retailers to curb shoplifting, can disturb the function of a variety of
pacemakers, according to a report in the March issue of the journal
Even so, it's safe for people with implanted pacemakers to walk through
antitheft system scanners, but they should avoid standing too close, says study
author Jacques Mugica, MD, an electrophysiologist at the Surgical Center Val
d'Or in Saint-Cloud, France.
Because pacemaker interference by electronic antitheft systems has been
controversial, French researchers exposed more than 200 pacemaker patients to
two leading systems in a medical examining room. Before and after exposure, the
pacemaker's function was analyzed. Additionally, an electrocardiogram (EKG) was
taken to record the heart's function during exposure for up to 30 seconds. The
study participants had three kinds of pacemakers made by seven
The data showed that the antitheft devices interfered with pacemaker
function in 17% of the participants. The "intermittent alarm" type of
antitheft system showed twice as many interferences as the "continuous
alarm" type of system.
The most common type of pacemaker disturbances were those that interfered
with the pacemakers' ability to regulate and sense the heart's rate and rhythm.
This problem lasted throughout the exposure. The exposures did not cause
problems with the pacemakers' programming, and only one patient developed heart
The lead author compares the effects of the systems' magnetic fields to
routine testing of pacemakers using a magnet, which is known to be safe for
brief periods. During magnet testing, a physician places a magnet over the
pacemaker, which turns off the device and allows the physician to observe the
functioning of the heart itself.
"We observed the same type of pacing abnormalities as previous studies,
though the incidence was much lower," says Mugica. "The use of
commercial antitheft systems, to mimic real life, may account for the
What about other electronic devices? "Pacemaker patients are often
anxious about cell phones and microwave ovens, but the risk of interference is
very low," says Jonathan Langberg, MD, director of the electrophysiology
lab and professor of medicine at Emory University in Atlanta. Langberg notes
that pacemakers are now designed to filter out electromagnetic
Many pacemakers now are programmed to prevent sensing disturbances,
according to Langberg. "But even in older models, interference results in a
missed beat or two and doesn't cause any symptoms," he says. "Only MRI
scans and radiation therapy to the chest cause serious pacemaker
Langberg says the effect of antitheft systems on implanted defibrillators,
an internal device designed to shock the heart if an abnormal rhythm occurs, is
not yet known.
- Electronic antitheft devices can cause disturbances in pacemakers. People
can still walk normally through them, but should avoid standing near them
- Many new pacemakers are designed to prevent sensing disturbances, but even
in older models, missing a couple of beats will not cause any symptoms in the
- MRI scans and radiation therapy to the chest are two things that can
interfere with a pacemaker.